When trimming, queries fail because of missing System.Math

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Since we use our GetRequiredRuntimeMethod wrapper method, the linker cannot see our dependency on on Math (e.g. in SqlServerMathTranslator); this is a regression from EF Core 5.0, where at least basic query usage does work with .NET SDK 6.0.

The proper fix for this in 7.0 is to stop using GetRequiredRuntimeMethod (tracked by #26288), but for 6.0 we can do a simpler, less risky change that would make the dependency known to the linker. Other scenarios may very well fail since EF Core 6.0 isn't trimming-ready.

Reported e.g. in npgsql/efcore.pg#2185